SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e752ba80e1709244891b3c25e475e653682fb450b150f7359a5483d3c5c0345' 
  AND token = 'ZtswF+yjakgDky8NQafcDGvjseySelvX0sDI134tnKQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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