SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f346d7bdf140f54d7d53a1f102d5fb424a2ca1887366e0f2c49fa529dab8d603' 
  AND token = 'BGeYrPU6KFGHmO8745L4wLsnK+YxWRI81huQ+11NgJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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