SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a77b70200184c599fc83cadad260512d31f9958545203cf3d81f6ce5c9914dde' 
  AND token = 'IpIbWbINkHruZAzoeWRXKaahK3XanRhtTs6q2sGK/hY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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