SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f05abbbd939e5273641fbf8b21b73a86932cf9fdb6d866924ca9446d6d05f7e' 
  AND token = 'zh5uTj3JuiZCtM5afZY2TfeVBujtDuShrA3GKcumH+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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