SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25be50f84dd739bc5eb25a9a78fb479a39e7dafcbe31706e50e966bf9bfa938f' 
  AND token = '2BeDVJG1VCxjqz+BPdZnwfXkyIPOEOgPidiQRFTggoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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