SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4ec3a227bc32693fbf4d79d5d6419f8138a6a4d53e6ee5bf4857b4b4d1bfe5a' 
  AND token = 'ql/ph5FdlnaHurVUa999N0v6pCa7GVcBQGaPVqhBRCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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