SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb24bf7355c340b48cf931ff1fec422432818e42764148e6ec6e2fc6432a7d24' 
  AND token = 'acjl+nEpH3iXb/qvu6vGK8KoWyUEIHwfV9RB2zAXcwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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