SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fb4e59c795f21bc358885656b16b1311848b3b1792aa1082b485141dfe7f54f' 
  AND token = 'cak/kFJ+6JkAs5fdcMF6WsxAFvC1J7Gt1R/LYJZM5io=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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