SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73f6ea1ca4973ceb430495b331068248ba384af19d268ec0df621d878648d249' 
  AND token = 'n1vYLM1WzJb4Tv4Auj/8lSK5fO0P8rU5ldYjDF6yp8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}