SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dbe7ef96499e57d0c27e1e1df6d204408bcae3134bdb714122cec33eadc218b' 
  AND token = 'BtGQQeToVe/ROvkDzSSeUllZ73HvMDRbf2uSeEQ0gYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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