SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8cc6186207c09c0ebef9b70202e1ff62b442a42403712fc2650770133467aa8' 
  AND token = 'Mxph2tGem/596PBmq8AL2hkxl0Tm2ZeNV8nvBylpHBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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