SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '383ba7944c31a02c2931b266c03cca1045534ead2e272307e399828dede34ac7' 
  AND token = 'e6ykelVOrlEUVxt4Otxf1Un6WUrNLmdTNqJWGfq2hx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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