SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d913dc10aeda6f75f82493365382f4fe4f17c16268c6a4ef4ebb761eaeb330' 
  AND token = 'I+rfJ5e/fwFz9AqjJI98hzotDmx19d9gVAZVoQnoABA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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