SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bea50588e543f33da71e0dc0678c13888dfaa27cf472532b2f5944d52f602828' 
  AND token = '18JqWoNL7/FnxcWSXhLkQ+f2DqHFU+Ez7oJo2cPh63g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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