SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea44c6d5f932bfe1e25c94ec626250643719aa65e7b275fe89b1bac4de0387a2' 
  AND token = 'Kqa5fLw2AbZyV3NhSiwNkiTyzpnxAii6ED37/tgH2JM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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