SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68cded4a587b7cd6d7cd01c60ed77dd18f8c72f041fec375f724cb3a09d47b22' 
  AND token = 'z+34wPDi6d2d/1inDTsaB8N+sVRhKlhzZphoyIpxjTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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