SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c6f5f7a482314a9320a9410d1e4eeeb1ad22addcc6a48281d03455ee2cd0936' 
  AND token = 'pVFVXhOZ0rYHOy/GORlVYfUuMnLIDyMowYwqPG4/yk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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