SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bf297f69b590c801243fc1345e9b76b79e3b5a644035e98f0c557f974bddd16' 
  AND token = '/PijgSu8ATDaCEpJ9/hmVCHOT1WBN9lKDwKS0Vvy218=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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