SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f449a391276d345908cbff87812bbae023940df94f18c4cf440781e6dbcaafaa' 
  AND token = 'F22apT+Ar2c2eVi3rtuazL7fwkEdpDwBfwb6sO5lP7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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