SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb2598503308641dbbd257e4d2a5dedd84118c42c42e1e10f06c668baadc645a' 
  AND token = 'bZG6dj9FGOYz7Oy03sbz0UFj+HIIxpKee9rWzkMSH7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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