SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f105451ec81ce165140455b8335c1bdf44ff04f0b202dd2ddcc7b0a80c628748' 
  AND token = 'FftbFkG3JDmm+jJHv3F8ySDqlB4TSUjf4jfhao/cIkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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