SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59bbcada77d2fd991773c393a13670a58fbe7ebb1273be998c5792f72604a7eb' 
  AND token = 'VWj9dlrAaM9/KuSTLPPeiulQREUnO/YVVqWLRYu+s28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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