SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e45924e068c650361ce0d81779fc0f7f564895a2502b3a9252a1cf540a8b872a' 
  AND token = '1xP7daBZ1+JV4Bs8kTSlnZXRjvi/WEH5KJl/GOpzlIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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