SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a2d59c1d579af5ea051e5d194e24cfb847ba404d08386f7dee0877ebc76b511' 
  AND token = 'Llyu5l20nye9y13iyvtzUmNC1QOT7Cb6PMYQ0f94s4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00078

JSON explain

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