SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f88a1209e992766d41249d3c5627e8193c22295158622c124d346c9875532df' 
  AND token = 'sZsscobljgu0Q1hBzJznLcraizPd/g4QQbrY+J+LPQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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