SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffe388cb51d9c7f7d24b0c9e5c086581443fe0ced6f1c5598975af38eb8dbf45' 
  AND token = 'gDwtnTWBg/qfTOZTMdUSVTdcJWuGlqRxptUGsIfWxCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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