SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf2de0eeb788114885caa7db9de1342feaeb5fdab9c7973b86b6ae3a0a2e663a' 
  AND token = 'DVRujAal4kBlK+cXynwXTGeYnES1Zx5hnX8AzgvD+Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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