SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f27f4f83188dfd68ac3ada5ebedc2ae5faebcaa8e9c5bdd1a73c4bd86261814a' 
  AND token = 'nayNjUCBEl2AJM/fgZfPzO+jvBmkKl9J09HyTFQv09w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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