SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0819cb7a9541e23b14866118fa8227c22b8b4b4c6d527b41153e91fcdbd7cb0c' 
  AND token = 'HwYfk4F6uYRmn/mMnItUXVT1/tn9dNEoMA04uVxHMw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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