SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdf42be75f726252a60bc9bd66f426a9e73ab372b5319e4ff01173559517283f' 
  AND token = '+nGWwoZEPKmOcDWa3QjURZtX1yryJt/UqWCgs0Uyu1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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