SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f0c9d738a7f67fefcf9a62ee37a845acee012125c79fe59ecdc693e469e14ae' 
  AND token = 'I9ZU35XN7gP3Tu2aGCOdEcl/3VioCdfDIot+f5IfDRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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