SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e168144fb2eea5e3555fdd3cf603422d18c902cb5a6c91f244482985cf2c6f9' 
  AND token = 'U35dQ2acPScSK9eOoNv63hK4MzZHD4WOLRM9gmagk1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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