SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0dd79a0402c972368766241458d4e2e30283d23ffc24facc426bf3e8f1832c4b' 
  AND token = 'gvY0rfBwOyZ0/dsQJaUm+afMUrojtPOHFiz6GheJfl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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