SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57170369046c8dda02b7cf96eebc3dbfa093ba8efcdb5b117397d75850968187' 
  AND token = 'JIvE3NUUHRXRlFGf9Wz1A9xPCYwDd5vusq/yqVPMc4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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