SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e520927833a55cb672dcfe0fabef914dca98246728522cfed6e31f078065c1c0' 
  AND token = 'vmTMzeZK+klBMwX8qehALZmkxeeK5YejroVLhj1D1AE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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