SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5672046a4973e43e138bbe59cedf7e064c6656fe06e8f748606ad373bd2d4072' 
  AND token = 'feU/lJrO1xFJlkB7QsfMUnAsChW+4ICGcAYrweq5VWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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