SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8816e5b06060abd5b43a322b6fecec95c6e20c321497edbd0fc6599cd689f0be' 
  AND token = 'R4giM74RqT9D3Lla2jAb95oBKwJ0XgUragBKeWJO/Zo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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