SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '213f875dfa52f3845988ec6ceb5cf503417ba673605a119e5eefec9e59f6747e' 
  AND token = 'dGJTx75PpVAlHcH8HW6NJHtxOcvvVigktOpnsYdWamE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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