SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75c7d7572b4f03681d0c762bc1a9f543b7e976b1bd5632476445b725b8b9eaae' 
  AND token = 'wropddF18+4hoHcZaBVlqzmAcZGj9EpeRdiQQu1H3Mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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