SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aca99ced4ddd8b27edab06c5bee8c551ac668ea41aa4165bb66123122332119f' 
  AND token = 'kSp1XHAAh7wVHHHE6XGSgBUDwr6A0offZMLGRQOsL/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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