SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59b25b21cfa8ca334eead06c06f5982c5883423e411fa4208eb6a04d4e5be4ba' 
  AND token = 'kIeXAkodaQS0qs8/8o8TKmlx6rw0UcGe4MJrRQ6v+iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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