SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d4cac05b649683f1587a5df99a7e21c43703570fdde890eb42219782e2a2e78' 
  AND token = 'BJKKUjEXn4imGmhX3M4UtEYssWEqyktoadaBNYkMZMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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