SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20cdfa5b324a06eabcde1f127889e29eb0625c4f2ee8652d6d8eb670279597ff' 
  AND token = 'I5Z1QmQlWcI1EryTnffa5d9L5Ak9+od8q/3eK2qhJPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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