SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44a552632364f17c03699adb4ce427f802ff13918192a520143b17948831c406' 
  AND token = 'Sj/Tj9xewV8I5qjTq/WvzWI/LhPyZOlYMkcc3Tj2Shk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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