SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b306426cf305b14915d754bbfa593505f89da90b26cea6f6cde9bbb875354ea6' 
  AND token = '/+OI2yyWjPqAghF8DLtJe3U8s3FOR0glb46T0Zhelrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}