SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '540ff78661437ff2e5625a2dafb9a271f7c4ab2f86b94b5519eaf2dad6c4027d' 
  AND token = 'FZQzYaBrvkhPLQ0CJ+oYYioX1KzvH/EuYcP/OybqvAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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