SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b58e3c10b90359576a4e1ee6e17d9bac20cd4af09cb74627d2df929cd44f20c' 
  AND token = 'eHvlXdak9AEm1EqAIb0wlsTlHZelOFLgbAnQ0X+UfCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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