SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '719a2b92d3314ff123113a93a84faa1498c99122835f86bcfc8ff4ab5c47c1cc' 
  AND token = 't4WFukeZxFx83GpR+CY4IUvmtXQj3KwL33G+9b5qRcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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