SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6e47624d7914c2653d4cedff3ef752f8aca8dd8ca97dcadcf531905d86dfd7e' 
  AND token = 'LsG+2THnDXh2dN0gElkDZVxiZvsliq7rdGZf9DTOO7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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