SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a70d143bd83f5c0ea8fd7a06576374a34e1ab562f7490ab4c2e217addc9634' 
  AND token = 'HCOX3NqKpcdOadTMfYcaL1JK8f2Exx4kadNhPdxifVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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