SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '883184f210fc1ca1f64e6385993e6164dd9bf5b19f1b6b9a71d2a2c9d5d3e17a' 
  AND token = 'qQYjgGNvL2FfBJNAfIDGp2/zVq64djJvd4mOzgiw5HI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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