SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c2e1a78c92e0582b7a99fb74629ca6cf680665134a45da0dc3f014a79604c64' 
  AND token = 'js3gz5oPVDSZfSpleRm+mRCfzj+JQxRL2xixFhFvhTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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