SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b73de5efdf9228b4d11bb8c225311d974896fad35697d5977ed6c4f691d1335' 
  AND token = 'gwcszDCQpn6UHLuys9zQNqgmIQUNY8VZAeHtEnKmI4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}