SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '377debd68188342d96b3ecb2ab3ddc8d0bb8f75f02adeb4aab1b2961c4fd7c7e' 
  AND token = '79fM6PlL8P5gakK+I5p/z7EfIMu1LHXO50+RFWh8LS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}