SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1a1e128e896e8623a6bbab1f5791dba717d3f50d43969cd940118c3e616f525' 
  AND token = 'GsTy8HYRhywx00IymNVQU3UHwYMRFF0xt81uNd6NFWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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