SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c179a2a88befd0c5085ba803bd2149f041934ed4097ef85c9301d5518c295b7b' 
  AND token = 'zaMcLQojoLJskFQ383llkJpAuKF0EgKfwGzRQjNApGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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