SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b28e23fb12c8d7638a4bab296a04bcf147f3adec4aa8df56cefc11b650eb86a' 
  AND token = '2xL6i6U4r4gZ8MZIpJeYPCgou7XTIpfulPlXqim3pQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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