SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cffedd35884e26d32424dfb3da0a7c268ce61d6c0edd6451b3e1b73dc49e0e73' 
  AND token = 'isuNM1ujWnpR2vyi8UYGjCCwgGCyhsiBUaoRfnWRKgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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