SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '536721c2d344cb19ffee96c4a41c868a46b5489fc29fa984b0937c8fd90753d7' 
  AND token = 'Q77gEy/wq/5PjprV3ExbibcaxZeSRZVng8sUnU0XRno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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