SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0eae006e618647c1ff6535198e6cf459def9c3e343b35a05e5619ce5bea201f' 
  AND token = 'ruZwkedxZn8fQNGTB1sbDXKmUvULddFf6nUq8/jpulk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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