SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b71eeb452da58088e007a79d7e0c4f0d9790988f63fe6af4daad8b0dd49e5926' 
  AND token = '8VQqk7klbJveFF8BN+kBm/dnksRoIbPxfaMRrf1RRAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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