SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb988089a556d4724b3738fb6fee3a67563a53e7e00b4d5b8405aa5b488fcd0c' 
  AND token = '5jcQnZZqm7XdT9FM/TWDQoV+/S/yNhjFmiDPPnVzcKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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