SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cbcfa16e12591774d7d8aaaac69f3b7d2c9e880f66de601453d3760f18ff6b8' 
  AND token = 'D/DIVtGw+RLYQjjnclGM65x3MLPt4ZGRMbv76RziPNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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