SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d15593dfef9f05e02b1013ea951829cbbf9d089465f172ca3606df0d1c5110a' 
  AND token = '6nPW8ZFWUDco9GsNQIfmZwSA/piEakOtazUa/2QwChg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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