SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd60082e9d1a809952dd73c1e9ef6adc9aa8e2304b64bff0678c550af13dfca82' 
  AND token = 'D8jVlQvcUxliWsTzn5bxsmoNiFGOVW0zp0kPTRZNX3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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