SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da5982181b39e69c835adff748309f9a77e1ad1a909dd5570935cd764372b3bf' 
  AND token = 'PCxTf9HGDVB381M4wKcKFj4azODtcQ8LOIYoiL4nOHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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