SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b40a18d6e99e9bd59209bb0cefb7ce9b3332d53d1ee104b9980289d9f2aac46' 
  AND token = 'UizmYZ6IP81wWAeI1lqHmQFT3nZX0/GddMehYf7+VW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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