SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b63b19dafc862cefcb18dfa7b09831c404b5df0fe05b9d4a14fa86a24c65bb17' 
  AND token = 'l8GhfYXB1GkAcuGafBWSEfNYStl458sMarEDFxgjgAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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