SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec2edf6febfc45a5711b1167a67e5789a868cdffa59581e042cf5b9599f62154' 
  AND token = 'iza2+Sf/VrsNKEbGHS9rpC8IWeMdpTgjkCDFyPfiCLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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