SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eed8c6bfe943a00e344d8f040eb73cda7ea2e285dbad749a4d556ba68924a2ac' 
  AND token = 'YtWm9hf6sfsYkSIcIWVVNODRdYJKmXgu2fXXCiHAHMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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