SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec00001ebbafded0c43f4cbd1113cbb9dbce148cb968d2328d6de947166680f0' 
  AND token = 'kklbElrvzoLlWKZHnXTrjZ0MCD4IZYTK1tn5B8HpYZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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