SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a47803abd694ec1fe2f95e2a2737cc94f999b48ab4429925526b0e28e556e4f8' 
  AND token = 'KDl2fA+w/2kOWW9SOre8LSjsDBnRntdUL8eTeOm2hf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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