SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20d39da3d7dbbc000eb06a70e2a2e2c58447c3063cb821289f393f844d25d933' 
  AND token = 'tlkx2llGt5KwWA4/TBJKufhGC+niMiChFHlOgpZ8N7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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