SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4912b231f1f1f59f54f2f47b66c5b35fde27382075f22c026e84ea846c6d2c8d' 
  AND token = 'MoIBAuNXHPHuzTyHJ27nTI9fWIQG2OeGHdlrAzIpNPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}