SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3e224a230ad84438a46d0d06ed345e2eccae5f1e5248fd3fd925a98fdada2e3' 
  AND token = 'n/vwozSSPagigE0GyXhqPNmhQAW2vFMYebR1pABHFqY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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