SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9368d90e4f16d251e58ed2e39f2d5b52bcd828c5661780cb9888eb0ef63cdbea' 
  AND token = 'QQLadFAE0P/37xFVrFplC6CUvgsySWZcFrOMuJE/EhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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