SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b461689f1d0e6d6b21b69c9af21a7e20494091d6e577c335f7f8faf30870dc06' 
  AND token = 'flQAZcZ+ljEdHvA5aZyxN/VN/X46nmt7wYBqVyqK+nU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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