SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a33838163fbe36d347df2475475760c29c60009d0ab12de17df16fbe8b0e12e' 
  AND token = 'EBo9DOIFkSbgLz/gR+bZQ7mG6yjEx7+/ynEPThQV8H8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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