SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31b7a04d6e937801675abb9907e935e2726979b456c8f76e832de1f541572876' 
  AND token = 'eELOQfdNyQWR9kk1yhzYpNkzDyNL81LJxtt3WuCfPfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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