SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f045400029434253e356ce1273e5c951ba7fbb83b899b9c44349825590169a74' 
  AND token = 'KlZMtuJwKj0TLaRt76W8Fikxh3hG1bUJPyacRNE1qmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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