SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a83643535cbca79153d2f9cd91c9dcc18751c373d0f307ac7f0892ef7ed38a3' 
  AND token = 'fZ2KeoZ/25Hch1CHDUzW2CF7MMI5rkEWOgk1YL48Jxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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