SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a00c4228f155fdfab0a273baf776073cc97d33368507d1762e24266fe7dddc7a' 
  AND token = 'YUScR5YdMYz0QF68XbPiWxvdr4aWYW8sgN1508lPNSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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