SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a742006a720f5cefb00b9d7668de2ed4268cd61f1a8a8bb193fb1e32e6be39c1' 
  AND token = 'GJTESk/df5eYeRpy7luQBYg8Z8i3z2fK+VS9+ebIlc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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