SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7aba0b0cb9cc1c93aa524268f8f168c0171792937ec18bf5860e73d3e400fabd' 
  AND token = 'h8pAwbHZfFqok2b/4rwBqq4bwpYwElYCiygDv67z/ms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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