SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb2f3b35bd97e5a22192293ec1cefe03118288bc9963fcba119396631ad64c32' 
  AND token = 'W1Nc0BmlBLMdupMND5HgMos6c5Exeae+FWWjTf7Ub/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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