SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37ca401206aaed4d932f5a0b1cd61ba935194b50cc0692186ddf3d6c030d3fbb' 
  AND token = 'WMznrVq2iQeLp4DUJOOTU2Sd5h4iInG9+0t9BJjM2NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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