SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3994e22ca0cfce3ab81dd294f8f483f270bf70b80cffe7939d653366eb4e96d' 
  AND token = 'EunhiP15cubjIy706OeYnyYn95sqg8LqrwnYkeoj0AU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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