SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9ef5ba90a96c8abd3e7bb3b43066a4bf3566ce55482a5b7466e0ffbee3415e4' 
  AND token = 'fQiU5XbuJL6tO/29MYpcAAEl5wAxpbVfpPTLObNLeVM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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