SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5639361105d20326dbfbcf3473ff30127008009faac0da7915b18ce79a8a92a' 
  AND token = 'iuwI7VgzAcmEm4wy/OTC4YtDaBiTeJW1AQZ2wSGxW+w=' 
  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"
    }
  }
}